• 한국분무공학회지
• /
• 제12권1호
• /
• pp.30-37
• /
• 2007

Dimethyl ether (DME) as an alternative fuel for compression ignition engine was investigated by measuring spray development processes, injection rate profiles, engine performance, and exhaust emission characteristics. The results of DME fueled engine were compared with those obtained by fueled with diesel. The experimental results showed that DME has approximately 0.03ms shorter injection delay and higher maximum injection rate than those of diesel fuel at a constant injection pressure of 50MPa. The spray visualization indicates that DME has shorter spray tip penetration due to its low density and faster evaporation. The combustion characteristics of DME operated engine provided faster ignition delay and three times shorter combustion duration. It is believed that the better evaporation and atomization characteristic of DME contributes the faster combustion. At all operating condition, soot emission was not detected due to the clean combustion of DME.

• 대한기계학회논문집
• /
• 제19권2호
• /
• pp.548-558
• /
• 1995

An experimental investigation has been conducted to study the spray and combustion characteristics using the air-assisted twin fluid atomizer. Axial mean and fluctuating velocity components as well as drop-size distributions in non-reaction spray were measured with a nonintrusive phase doppler technique. Droplet number density distributions were also visualized using high speed CCD camera. Locations of spray and flame boundaries are obtained by direct photographic method. It is confirmed that at the fixed fuel flow rate, the increase of the atomizing air flow causes improvements on both spray and combustion characteristics under stable flame conditions. Internal group combustion modes where flame is located inside the spray boundary are observed to exist in the upstream region of higher droplet number density.

• 대한기계학회논문집B
• /
• 제35권1호
• /
• pp.67-73
• /
• 2011

본 연구는 DME-바이오디젤 혼합연료의 분무 및 연소, 배기 특성을 바이오디젤과 비교한 실험적 연구이며 실험연료는 바이오디젤 (BD100)과 중량 기준으로 DME를 20% 혼합한 DME-바이오디젤 혼합연료 (B-DME20)이다. 거시적 분무 특성을 연구하기 위하여 분무 이미지로부터 분무도달거리, 분무각을 측정하였으며, 연소 및 배기 특성은 단기통 직접 분사식 압축착화 기관을 이용하여 분석하였다. 실험결과 바이오디젤과 DME-바이오디젤 혼합연료는 분사율에서는 큰 차이가 없었지만 혼합연료의 경우에 착화지연기간이 짧고 연소압력이 높았으며soot 배출물이 현저하게 줄어들었다.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2000년도 춘계학술대회논문집B
• /
• pp.913-918
• /
• 2000

Spray and combustion characteristics were investigated to find suitable injection pressure by using ultra high pressure injection and single shot diesel combustion systems. As injection pressure was increased, spray penetration and spray angle were increased continuously until 2,000bar, but after this injection pressure region the rate of increase was decreased suddenly. Combustion characteristics were also enhanced until 2,000bar of injection pressure.

• 한국추진공학회지
• /
• 제22권1호
• /
• pp.72-79
• /
• 2018

초음파 진동자에 의해 미립화된 케로신 분무연소의 OH 라디칼과 CH 라디칼의 자발광 특성을 고찰하기 위한 실험이 수행되었다. ICCD 카메라를 이용하여 분무화염의 자발광 강도를 측정하였으며, 연소 시 소모된 연료량은 정밀유량측정법으로 계측하였다. 그 결과, 연료소모율은 수송기체인 공기 공급유량에 선형적으로 증가하였으며, 분무연소의 특징인 전형적인 그룹 연소가 관찰되었다. OH 라디칼과 CH 라디칼을 분석한 결과, 분사방향으로의 유량 증가에 따라 라디칼 방사강도의 최댓값은 감소하고 그 위치는 후류로 이동하여 반응대의 폭은 증가하였다.

• 한국분무공학회지
• /
• 제25권2호
• /
• pp.51-59
• /
• 2020

The purpose of this study is to propose and compare methods for measuring individual spray cone angles using spray cross-section images. In direct injection gasoline engines, it was believed that the distribution of air-fuel mixture in the combustion chamber directly affected combustion performance and emission formation. However, since gasoline direct injection (GDI) injectors have a small injection angle, interference between individual spray plumes occurs. Therefore, GDI injectors have only measured the spray angle of the entire spray. To overcome these limitations, three methods of indirectly measuring the spray cone angles of individual spray plume were presented and compared by forming sheet beams using Nd:YAG laser and acquiring spray cross-section images. Each method currently has advantages and disadvantages, and research to apply the method suitable for various GDI injectors needs to be continued.

• 한국분무공학회지
• /
• 제17권3호
• /
• pp.113-120
• /
• 2012

It is being more serious problems that the pollutant and the greenhouse gas emitted from the internal combustion engines due to the increasing demand of automobiles. To counteract this, as one of the ways has been studied, GDI type engine, which is directly injected into the combustion chamber and burns by a spark ignition that chose the merits of both gasoline engine and diesel engine, was appeared. The combustion phenomena in this GDI engine is known to contribute to combustion stability, fuel consumption reduction and reductions of harmful substances of exhaust gas emission, when the fuel spray of atomization being favorable and the mixture formation being promoted. Accordingly, this study analyzed the affection of ambient temperature and fuel injection pressure to the fuel by investigate the visualization of combustion, combustion pressure and the characteristic of emission, by applying GDI system on the constant combustion chamber. As a result, as the fuel injection pressure increases, the fuel distribution in the combustion chamber becomes uniform due to the increase of penetration and atomization. And when ambient temperatures in the combustion chamber become increase, the fuel evaporation rate being high but the penetration was reduced due to the reduction of volume flux, and confirmed that the optimized fuel injection strategy is highly needed.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2008년도 추계학술대회B
• /
• pp.3019-3025
• /
• 2008

An experimental study was performed to assess the effect of diesel and JP-8 aviation fuel on the spray characteristics, performance and emissions in a single cylinder optical diesel engine. Both fuels were injected via an 8-hole solenoid-driven injector in a common-rail injection system. For better understanding of spray development, the macroscopic images were captured with high speed camera, offered evidences for the results of performance and emissions. From macroscopic spray images, the spray tip penetration of JP-8 shorter than that of diesel while spray angle of JP-8 was wider than that of diesel. It indicates that the vaporization of JP-8 is superior to that of diesel. The lower cetane number of JP-8 resulted in increased portion of premixed combustion. The IMEP with JP-8 is lower than that of diesel-fueled engine. Especially, using JP-8 has a potential for reducing soot.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2007년도 춘계학술대회B
• /
• pp.3329-3334
• /
• 2007

The purpose of the research is to investigate of diesel spray combustion for simultaneously reduce way NOx and PM. The pressure diesel injection were done into intermediates that are generated by very lean DME HCCI combustion using a RCM. The concentration of intermediate could not be directly measured; we estimated it by CHEMKIN calculation. DME HCCI characteristic is surveyed. Validations of the CHEMKIN calculation were confirmed pressure rise of an experiment and pressure rise of a calculation. Using a framing streak camera captured two dimensional spontaneous luminescence images from chemical species at low temperature reaction(LTR) and high temperature reaction (HTR). Also, the combustion events were observed by high-speed direct photography, the ignition and combustion were analyzed by the combustion chamber pressure profiles.

• 한국추진공학회:학술대회논문집
• /
• 한국추진공학회 2010년도 제34회 춘계학술대회논문집
• /
• pp.411-414
• /
• 2010

초음속 엔진에서 흡입구의 buzz현상은 큰 압력진동과 연소 불안정성 그리고 추력 감소 등을 야기한다. 흡입구의 buzz현상과 액적 분사/연소의 동적인 상호관계를 이해하기 위하여 통합된 비정상 연소수치해석을 수행하였으며, 액적 모사를 위하여 TAB(Taylor Analogy Breakup) model을 적용하였다. 흡입구에서의 충격파거동과 주요 위치에서 압력거동을 분석하고 초음속 엔진 전영역에서의 음향모드를 분석하여 현 시스템의 동적거동을 파악하였다.